1. Field of the Invention
The present invention relates to a laser scanning microscope for detecting transmission-light and/or reflected light from a sample or fluorescence generated from the sample when a sample has been scanned with coherent light outputted from a laser beam source.
2. Description of the Related Art
A laser scanning microscope is used for observation of a variety of samples. For example, in the case where a biological sample is observed, fluorescence observation is often carried out by applying a fluorescence dye to the sample. In a general laser microscope, fluorescence light is very weak, and thus, it is a routine to insert a laser cutting filter for cutting laser beam for fluorescence excitation or a filter having wavelength characteristics in which laser cutting can be carried out for a fluorescence band pass filter. This laser cutting filter-requires a characteristic of OD (optical density) of 4 or more in the practical point of view.
In addition, in U.S. Pat. No. 6,094,300, there is disclosed a laser microscope (hereinafter, may be referred to as a “above and below” microscope) in which laser scanning optical systems have been disposed at the both of upper side and lower side of a sample.